This invention relates to apparatus for minimizing damage to a continuous caster due to breakout of molten metal from a partially solidified casting at a location downstream from the mold, and particularly to apparatus for providing a signal giving early warning of breakout of molten metal from the strand at a location adjacent to a downstream end of the mold.
In the continuous casting of molten steel, breakouts sometimes occur where liquid steel from the core of a partially solidified cast strand leaks out through a break in the skin at a location just downstream from the mold. When this happens considerable damage can be caused to the rolls and other equipment below the mold, especially if the caster operator is not made aware of the breakout until substantial quantities of liquid steel pour out from the strand onto said equipment. The resultant damage significantly increases the amount of downtime of the caster required for repair and restart of caster operation. It is desirable to obtain an early warning of the breakout of molten steel from the cast strand below the mold so as to minimize equipment damage and downtime of caster operation.
U.S. Pat. No. 3,834,445, Raschke discloses apparatus for providiang early warning of breakout of molten metal below a continuous caster mold. The apparatus includes a protective body resistant against molten metal located immediately below the mold. The body is provided with a cavity open towards the shell of the cast strand for receiving liquid metal therein. In the cavity a sensor is provided in the form of a wire which is electrically connected to one pole of an alternating current power supply. The other pole of the power supply is connected to a line leading to an alarm. When liquid steel breaks through the shell it collects in the cavity and closes a circuit between the wire and the body on the strand and the mold so that the alarm is actuated. A disadvantage of this apparatus is that the body may require circulation of cooling water to prevent damage to it by heat from the strand prior to a breakout. Also, the body is part of a permanent fixture beneath the mold and may be cumbersome to replace in the event of damage by a breakout.
U.S. Pat. No. 3,593,773 discloses a pipe having an opening for receipt of steam emitted within an enclosed area from the core of a cast tubular shaped strand. The pipe transmits pressure to a measuring device which detects pressure changes that may indicate abnormalities such as the formation of cracks in the strand beneath this mold.
Other patents pertinent to the field of this invention are U.S. Pat. Nos. 3,537,505; 4,542,781; 4,553,604 and 4,607,681.